“Yemen, Sudan, Jordan and Syria all look vulnerable. However, the greatest risk in terms of both probability and severity is in Saudi Arabia,” said a report by risk consultants Exclusive Analysis.
While markets have focused on possible disruption to the Suez Canal, conduit for 8pc of global shipping, it is unlikely that Egyptian leaders of any stripe would cut off an income stream worth $5bn (£3.1bn) a year to the Egyptian state.
“I don’t think the Egyptians will ever dare to touch it,” said Opec chief Abdalla El-Badri, adding that the separate Suez oil pipeline is “very well protected”. The canal was blockaded after the Six Days War in 1967.

There has been less focus on the risk of instability spreading to Saudi Arabia’s Eastern Province, headquarters of the Saudi oil giant Aramco. The region boasts the vast Safaniya, Shaybah and Ghawar oilfields. “This is potentially far more dangerous,” said Faysal Itani, Mid-East strategist at Exclusive.

“The Shia are 10pc of the Saudi population. They are deeply aggrieved and marginalised, and sit on top of the kingdom’s oil reserves. There have been frequent confrontations and street fights with the security forces that are very rarely reported in the media,” he said.